arm64: Run ARCH_WORKAROUND_1 enabling code on all CPUs

Commit b5e63f7dafef ("arm64: Advertise mitigation of Spectre-v2, or lack
thereof") changed the way we deal with ARCH_WORKAROUND_1, by moving most
of the enabling code to the .matches() callback.

This has the unfortunate effect that the workaround gets only enabled on
the first affected CPU, and no other.

In order to address this, forcefully call the .matches() callback from a
.cpu_enable() callback, which brings us back to the original behaviour.

Fixes: b5e63f7dafef ("arm64: Advertise mitigation of Spectre-v2, or lack thereof")
Cc: <stable@vger.kernel.org>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 88966496806ae3fb6179859ab61123f7df9e61e1..3fe64bf5a58d40786a8539b3e6ead3fe94003194 100644 (file)
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -599,6 +599,12 @@ check_branch_predictor(const struct arm64_cpu_capabilities *entry, int scope)
        return (need_wa > 0);
 }
 
+static void
+cpu_enable_branch_predictor_hardening(const struct arm64_cpu_capabilities *cap)
+{
+       cap->matches(cap, SCOPE_LOCAL_CPU);
+}
+
 static const __maybe_unused struct midr_range tx2_family_cpus[] = {
        MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN),
        MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2),
@@ -890,9 +896,11 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
        },
 #endif
        {
+               .desc = "Branch predictor hardening",
                .capability = ARM64_HARDEN_BRANCH_PREDICTOR,
                .type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM,
                .matches = check_branch_predictor,
+               .cpu_enable = cpu_enable_branch_predictor_hardening,
        },
 #ifdef CONFIG_RANDOMIZE_BASE
        {